000
FXUS63 KGID 021050
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
550 AM CDT SUN AUG 2 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 336 AM CDT SUN AUG 2 2015
A WEAK COLD FRONT IS EXPECTED TO WORK ITS WAY DOWN FROM THE NORTH
THIS AFTERNOON WITH TEMPERATURES SPIKING AHEAD OF ITS PASSAGE DURING
THE EARLY TO MID AFTERNOON HOURS. AS TEMPERATURES CLIMB TO NEAR THE
CONVECTIVE TEMPS AND WEAK FORCING IS REALIZED FROM THE
AFOREMENTIONED FRONT...CANNOT RULE OUT THE POSSIBILITY OF
ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT DURING THE LATE
AFTERNOON THROUGH EARLY EVENING HOURS. LATEST MODELS ARE STARTING
TO PICK UP ON THIS...WITH THE RAP/NAM/HRRR AND EC ALL INDICATING
CONVECTIVE DEVELOPMENT AFTER 18Z. AS A RESULT...INCREASED HIGH
TEMPERATURES A COUPLE OF DEGREES TO ACCOUNT FOR ADIABATIC
COMPRESSION AHEAD OF THE FRONT...AND INCREASED CHANCES FOR SHOWER
AND THUNDERSTORM DEVELOPMENT DURING THE LATE AFTERNOON HOURS.
WITH LITTLE UPPER LEVEL SUPPORT OR STRONG SURFACE FORCING...EXPECT
ANY AFTERNOON CONVECTION TO BE PRIMARILY DIURNALLY/OUTFLOW
BASED...DIMINISHING IN STRENGTH/COVERAGE AFTER SUNSET. THAT
SAID...DURING THE PEAK AFTERNOON HOURS...INSTABILITY IS EXPECTED
TO SURGE TO NEAR 3000 J/KG...ALONG WITH MODEST 0-6KM SHEAR
VALUES...SO STRONG TO MARGINALLY SEVERE THUNDERSTORMS ARE NOT OUT
OF THE QUESTION. NOT SURPRISINGLY...THE ENTIRE OUTLOOK AREA IS
HIGHLIGHTED IN A MARGINAL RISK FOR SEVERE WEATHER TODAY FROM SPC.
FOR TONIGHT...EXPECT TEMPERATURES TO COOL NICELY BEHIND THE PASSING
FRONT...WITH SEASONABLY COOL OVERNIGHT LOWS FORECAST. LOWERED
FORECAST LOWS JUST A TOUCH...PRIMARILY ACROSS THE NORTHERN PORTION
OF THE FORECAST AREA...AS CLEARING SKIES AND LIGHT WINDS SHOULD
ALLOW FOR DECENT RADIATIONAL COOLING EARLY MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 336 AM CDT SUN AUG 2 2015
PRIMARY FORECAST CONCERN THOUGH THE LONG TERM REVOLVES AROUND
THUNDERSTORM CHANCES.
THE PERIOD STARTS OUT MONDAY MORNING WITH MODELS SHOWING
NORTHWESTERLY FLOW IN PLACE IN THE UPPER LEVELS ACROSS THE AREA. A
LARGE AREA OF LOW PRESSURE IS EXPECTED TO BE LOCATED OVER ONTARIO
WITH TROUGHING EXTENDING SOUTH INTO THE ERN CONUS...A NW/SE
ORIENTATED RIDGE AXIS LIES FROM OK INTO MT WHILE A SHORTWAVE
DISTURBANCE IS PUSHING INTO THE CENTRAL ROCKIES. AT THE SFC...MODELS
IN GENERAL ARE IN DECENT AGREEMENT...SHOWING A BOUNDARY ACROSS
ROUGHLY THE CENTRAL PORTION OF THE CWA...AS HIGHER PRESSURE IS
POKING INTO NRN PORTIONS OF NEB...WHILE LOW PRESSURE REMAINS OVER
KS. WHILE THERE CONTINUES TO BE SOME DIFFERENCES WITH EXACTLY WHERE
THIS FRONT SETS UP INITIALLY OR MEANDERS WITH TIME...THIS FRONTAL
BOUNDARY MAY BE A PLAYER IN OUR WEATHER DURING THE MON/TUE TIME
FRAME.
DURING THE DAYTIME HOURS ON MONDAY...MADE ONLY MINOR ADJUSTMENTS TO
THE INHERITED SLIGHT CHANCE POPS ACROSS NRN PORTIONS OF THE CWA. THE
00Z ECMWF CONTINUES TO SUGGEST THAT THE DAYTIME HOURS WOULD LIKELY
BE DRY...BUT OTHER MODELS SHOW THE POTENTIAL FOR SOME PRECIP IN AN
AREA OF INCREASED LOWER TO MID LEVEL ISENTROPIC LIFT NEAR A
BOUNDARY/ZONE OF CONVERGENCE. BETTER LIFT WILL BE WORKING ITS WAY IN
LATER IN THE DAY AND POST 00Z...AS A SHORTWAVE UPPER LEVEL
DISTURBANCE EMERGES ONTO THE PLAINS OUT OF CO. THIS ALONG WITH THE
POTENTIAL FOR A 30-ISH KT LLJ NOSING TO THE AREA WILL HELP WITH
DEVELOPMENT OF THUNDERSTORMS. MODELS DO VARY SOME WITH EXACTLY WHERE
THE SFC BOUNDARY IS SET UP...BUT MOST POINT TO IT BRING NEAR/OVER
THE SRN HALF OF THE CWA.
CONFIDENCE IN THE LOCATION OF SFC FEATURES AS WE GET INTO TUESDAY IS
LOWER...AS ANY ACTIVITY FROM MON/MON NIGHT WOULD LIKELY PLAY A BIG
ROLE IN WHERE THINGS START THE DAY. SIMILAR TO MON/MON NIGHT...KEPT
POPS IN THE 30-40 PERCENT RANGE DUE TO THE AMOUNT OF DETAILS YET TO
BE WORKED OUT...BUT SOME MODELS SHOW THE CHANCE FOR A COMPLEX OF
PRECIP TO BE WORKING ITS WAY ACROSS KS THROUGH MUCH OF THE DAYTIME
HOURS ON TUESDAY AS ONE DISTURBANCE PUSHES THROUGH. ANOTHER
DISTURBANCE IS SHOWN TO BE WORKING ITS WAY OUT OF MT/WY...AND WHILE
THE BEST FORCING OVERNIGHT WITH THE LLJ IS SE OF THE CWA...BETTER
FORCING WITH THE EXIT REGION OF A 60-70ISH KT UPPER LEVEL JET STREAK
LOOKS TO ACCOMPANY THE DISTURBANCE...AND JUST CANT COMPLETELY RULE
OUT PRECIP IN ANY AREA OF THE CWA TUES/TUES NIGHT.
THE CWA IS INCLUDED IN BOTH THE DAY 2 AND DAY 3 MARGINAL RISK FROM
SPC DUE TO THE POTENTIAL FOR THAT SFC BOUNDARY TO BE IN THE AREA.
THERE ARE SOME PRETTY NOTABLE DIFFERENCES BETWEEN MODELS WHEN
LOOKING AT MUCAPE /NO SURPRISE THE NAM IS HIGHER/ BUT EVEN THE GFS
SHOWS MODEST VALUES...AND WHILE DEEPER LAYER SHEAR VALUES ARE NOT
OUTSTANDING...THEY ARE SUFFICIENT /BETTER TUES AND TUES NIGHT THAN
MON/ SO THAT STRONG/SEVERE THUNDERSTORMS ARE A CONCERN...AND HAVE
INSERTED A MENTION IN THE HWO FOR BOTH DAYS.
AS FAR AS TEMPERATURES GO MON/TUES...WITH THIS SFC BOUNDARY IN THE
AREA...A PORTION OF THE CWA IS GOING TO BE UNDER THE INFLUENCE OF
EASTERLY WINDS AND POSSIBLY A TOUCH MORE IN THE WAY OF CLOUDS...AND
WOULD LIKELY HAVE A HARDER TIME WARMING UP THAN LOCATIONS CLOSER
TO/SOUTH OF THE BOUNDARY. MON HIGHS RANGE FROM THE MID 80S NORTH TO
LOWER/MID 90S SOUTH...WITH TUES IN THE LOWER/MID 80S CWA-WIDE.
LOOKING AT WED INTO THE FIRST HALF OF THE WEEKEND...WHILE THE UPPER
LEVEL FLOW /THANKS TO THE PREVIOUS DAYS DISTURBANCES/ IS STARTING
OUT MORE ZONAL IN NATURE...MODELS SHOW HIGH PRESSURE OVER THE AZ/NM
AREA TRYING TO BUILD NORTH WITH TIME WHILE SHIFTING SOME TO THE
EAST...BY 12Z FRIDAY LOOKS TO BE MORE CENTERED OVER NM/TX. THIS
SHOULD BRING MORE NWRLY FLOW TO THE AREA...BUT APPEARS THAT IT WOULD
BE MORE OF A NWRLY/ZONAL BLEND...AS THAT RIDGE AXIS JUST CANT PUSH
FAR ENOUGH NORTH. AS A RESULT...THE CWA POTENTIALLY REMAINS IN THE
PATH OF ANY SHORTWAVE DISTURBANCE RIDING AROUND THE EDGE OF THAT
HIGH. THESE PERIODIC WAVES WILL BRING CHANCES OF THUNDERSTORMS TO
THE CWA...AND IT IS DIFFICULT AT THIS POINT TO COMPLETELY DRY OUT
ANY PERIOD THROUGH SATURDAY...THOUGH THE FRI/SAT RIGHT NOW LOOKS TO
HAVE THE BEST CHANCE OF HAVING POPS COMPLETELY REMOVED IF MODELS
CONTINUE THEIR TRENDS. WILL HAVE TO SEE WHAT THE COMING DAYS BRING.
OTHERWISE...HIGHS WED THROUGH SAT DONT LOOK TO SWING ANY NOTABLE
SWINGS...GENERALLY TOPPING OUT IN THE 70S/80S...THOUGH A FEW 90S
CANT BE RULED OUT /MAINLY IN THE SOUTH/.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 545 AM CDT SUN AUG 2 2015
A WEAK COLD FRONT WILL SAG SOUTH ACROSS THE LOCAL AREA THIS
AFTERNOON BRINGING A SMALL CHANCE FOR A SHOWER OR THUNDERSTORM TO
BOTH TERMINALS DURING THE LATE AFTERNOON THROUGH EARLY EVENING
HOURS. AHEAD OF THIS FRONT...EXPECT SOUTHERLY WINDS NEAR 10
KTS...EVENTUALLY TRANSITIONING AND BECOMING NORTHERLY DURING THE
LATE EVENING AND OVERNIGHT HOURS. OVERALL...VFR CONDITIONS ARE
EXPECTED THROUGH THE PERIOD OUTSIDE A TSRA MOVING ACROSS EITHER
TERMINAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI